Voltammetric investigation of the interactions between superoxide ion and some sulfur amino acids

N-Acetyl-l-cysteine, l-cysteine and reduced glutathione, containing a free thiol group, behave as antioxidants, since affect the reaction pathway of the superoxide ion, O2-, electrochemically generated, in protic and aprotic media. Superoxide ion does not oxidize the S atom to oxidation states higher than that of disulfide.